Electromechanical actuator arrangements have been used for many years to achieve energy-efficient and precise motion of different objects. Typical applications are motion of lenses in optical systems, positioning of objects under a microscope, control of ink jet nozzles, etc.
In a typical prior art electromechanical actuator system, an object to be moved is attached to a shuttle. The shuttle is moved by action of an electromechanical actuator. The load of the object and the shuttle is acting against a support part, typically by means of bearings. The bearings can be linear or rotational depending on the required motion. For high precision positioning applications, very high demands are put on the actuator as well as on the bearing arrangements. Typically, the actuator is responsible for the accuracy in the driving direction, i.e. the travel distance, while the bearing arrangement takes care of the flatness and straightness of the travel, as well as the yaw, pitch and roll accuracies. The standard linear bearings of today may provide flatness and straightness in the order of 2 μm, and pitch, roll and yaw accuracies down to about 100 μrad. Typical allowable loads can then be as high as 500 N.
A problem with electromechanical actuator systems of today is that the bearing arrangements add to the total volume and in order to further reduce sizes of the electromechanical actuator systems while maintaining or even improving the accuracies very expensive solutions according to prior art have to be considered. At the same time, the loads are often much lower than the maximum limit, giving a very high load margin.